A commonly known method for manufacturing styrene is the coproduction of propylene oxide and styrene starting from ethylbenzene. In general, such process involves the steps of (i) reacting ethylbenzene with oxygen or air to form ethylbenzene hydroperoxide, (ii) reacting the ethylbenzene hydroperoxide thus obtained with propene in the presence of an epoxidation catalyst to yield propylene oxide and 1-phenyl-ethanol, and (iii) converting the 1-phenyl-ethanol into styrene by dehydration using a suitable dehydration catalyst. The present invention particularly focuses on the last step, i.e. the dehydration of 1-phenyl-ethanol to yield styrene.
The synthesis of styrene is important because this product functions as starting material for valuable commercial products such as plastics and the like. A disadvantage of these processes is the formation of heavy by-products especially if these by-products are formed from valuable starting compounds. Phenol and ethylphenol are generally present in the feed to the dehydration unit. Both phenol and ethylphenol have been observed to react with 1-phenylethanol thereby forming mono- and polyalkylated phenols. This not only results in heavy by-product being formed but also results in the consumption of a valuable starting compound. A solution to this problem would be the removal of phenol and ethylphenol from the feed before dehydration. However, phenol and ethylphenol are difficult to separate from 1-phenylethanol and such separation process would be cumbersome and expensive.